302 BOTANICAL GAZETTE [NOVEMBER 
normal fruits. In general, a fungus was said to be “injured” 
by that concentration of the deleterious agent which prevented 
its classification in class I as above. 
In discriminating between class III (inhibited spores) and 
class IV (killed spores) attention is again called to the impor 
tance of avoiding dunches of spores in making the inoculation. 
In many solutions such bunches— doubtless containing air— 
float on the surface of the drop and fail to receive the full 
influence of the agent. When spores from such a culture are 
transferred to pure beet infusion to test their vitality the bunch 
may be broken up in the process and the spores germinate — 
readily while all others are dead. Much can be done with care 
in making the inoculation, but at best it is a serious source of 
error, and it has been on this account, and on account of the 
impossibility of transferring the spores without taking with 
them small quantities of the agent, that the inhibiting concentra- 
tion rather than that causing death has been adopted as the chief 
critical point in discussing the experimental data. us 
To illustrate what has been said regarding t 
notes on cultures, a typical left-hand page of the cu 
book is here reproduced. This will also aid the reade 
stand the classification of the experimental data 
The opposite page was always reserved for more exten a 
on points observed from time to time in the progress Of © 
experiment. 
Sources of error—Before proceeding t 
experimental data it might be well to mention 
of error observed during the preliminary stu 
_ against in the progress of the work. 
1. Xylonite cells were found to hav 
on some fungi when used for hanging-drop cu 
2. Bacterial contamination. oS 
3. Lack of equilibrium in vapor pressures in the cells. : ef 
: details of itl 
he taking of 
Iture note- 
r to under- 
oa discussion of the 
briefly the source 
dy and | 
e an injurious jabnent 
Itures at 28 C. : 
4. Deterioration of stock solutions (see 
ment with KCN). 
5. Use of impure vaseline for sealing cells. 
